Spelaeochthonius Morikawa, 1954, which comprises 11 species, is a genus in the family Pseudotyrannochthoniidae Beier, 1932. Members of this group can be represented by troglobitic characterisitics and narrow-range endemism. Three species are documented on the Korean Peninsula: Spelaeochthonius cheonsooi You, Yoo, Harms and Harvey, 2022; S. dentifer Morikawa, 1970; S. seungsookae You, Yoo, Harms & Harvey, 2022. In this study we utilize ten species, including three recorded Korean species, two Japanese species, and five new species, for molecular analysis. We employ four genes (COI, H3, 18S, 28S) commonly used in pseudoscorpions studies. This study aims to (i) identify the most specific gene for species identification in pseudoscorpions, (ii) demonstarate the narrow-range endemism of Spelaeochthonius, and (iii) explore the speciation pathway of this genus. Consequently, our understanding of biodiversity and necessity of species conservation.

• Kyung-Hoon Jeong(Department of Agricultural Convergence Technology, Jeonbuk National University, Korea, Lab of Insect Phylogenetics & Evolution, Department of Plant Protection & Quarantine, Jeonbuk National University, Korea)
• Sora Kim(Department of Agricultural Convergence Technology, Jeonbuk National University, Korea, Lab of Insect Phylogenetics & Evolution, Department of Plant Protection & Quarantine, Jeonbuk National University, Korea)